1. Field of the Invention
The invention relates to an exterior rear view mirror housing with several housing parts, an exterior rear view mirror as well as an exterior rear view mirror configuration in which the housing parts contain the mirror glass.
2. Description of the Related Art
An exterior rear view mirror configuration for a motor vehicle consists, for example, of a mirror foot arranged on the motor vehicle, which can be covered by a mirror foot cover, and an exterior rear view mirror arranged on the mirror foot. The mirror foot can be produced as a die-cast piece, for example, from a material which is resistant to the forces and moments which occur. The exterior rear view mirror comprises an exterior rear view mirror housing, which, among others, accommodates a base support assigned to the mirror foot.
The mirror foot and the base support are hinged together, so that the exterior rear view mirror can be pivoted about a hinge axis towards the mirror foot from an operating position to a folding point and vice versa. In this process, bearing means can be provided between the mirror foot and the base support, in order to keep wear and tear and frictional forces arising during movement as low as possible.
Preferably, the base support is also produced as a die-cast part from a material resistant to arising forces and moments, for example, from the same material as the mirror foot. An adjusting device for a mirror glass, driven by an electric motor, for example, is arranged on the mirror foot. The adjusting device acts on a carrier plate, on which the mirror glass is arranged. The mirror glass can be mounted onto the carrier plate by means of an adhesive connection, for example. The carrier plate can be guided to and/or mounted on the adjustment device and/or the base plate.
On its rear side, facing away from the direction of movement of the motor vehicle in the operating position, the exterior rear view mirror housing comprises an opening, through which the mirror glass is visible, or in which the mirror glass is arranged. In order to ensure that the mirror glass is adjustable, a distance is kept on all sides between the mirror glass or carrier plate and the walls of the exterior rear view mirror housing surrounding the opening, so that a clearance is given around the mirror glass between the walls of the exterior rear view mirror housing surrounding the opening.
In addition, the exterior rear view mirror can comprise a repeated flashing light, a module for a driving assistance device, such as blind spot monitoring, a lane departure warning, approach monitoring, or similar, or a combination thereof. Alternatively or additionally, the exterior rear view mirror can also comprise sensors for recording driving and/or surrounding conditions, such as for example, temperature, brightness, degree of pollution, lighting situation, for example, in order to automatically heat the mirror glass, or to dim electro-chromatically, for example.
For example, in order to facilitate assembly of the different component parts housed inside the exterior rear view mirror housing, as well as, if necessary, their electrical connections to each other in an exterior rear view mirror of this type, the exterior rear view mirror housing is formed in at least two parts. A first housing part forms the housing base, for example, with a second housing part forming the housing cover, for example. One of both housing parts contains the housing section lying around the opening for the mirror glass, with the walls encompassing the opening.
A generally known and as yet unresolved problem of exterior rear view mirrors of this type is noise generation at high speeds.
An exterior rear view mirror is known in DE 103 51 857 A1, in which a protrusion is provided for reduction of noise generation. The protrusion is arranged in the area of the outer surface of the exterior rear view mirror housing, in which, the exterior flow is slowed down during inflow in the direction of travel, and after a previous decrease of pressure, a pressure increase ensues in the boundary layer. A laminar-turbulent transition of the boundary layer is enforced by the protrusion. The boundary layer, turbulent after the change, has a stronger exchange with the exterior flow than a laminar boundary layer.
Therefore, the turbulent boundary layer can follow a pressure increase for longer without displacement, and more easily than the laminar boundary layer. Furthermore, the separation bubble occurring on the rear side at high speeds is reduced, which therefore also reduces the trail. Both effects can contribute to a reduction in noise generation. The disadvantage of this is that, in comparison to the laminar boundary layer, the turbulent boundary layer has a greater thickness, connected to greater air resistance.
In DE 196 32 620 C1, an exterior rear view mirror is known, which is permeated by air ducts for reduction of noise generation, which are connected to an air source. The air ducts end on the rear side of the exterior rear view mirror housing. With this procedure, air should be supplied to the separation bubble which occurs on the rear side at high speeds, whereby the pressure in the separation bubble should be raised. Due to the raised pressure in the separation bubble, the trail of the exterior rear view mirror is reduced, synonymous with a reduced degree of turbulence in the trail. The disadvantage of this is the danger of additional, speed-dependent noise generation of the air ducts, for example, whistling noises.
An exterior rear view mirror is known in DE 197 43 107 C2, on which exterior rear view mirror housing, seen from the underside of the front stagnation point, before the transition or the edge to the rear side comprising the opening for the mirror glass, a tear-off edge is formed. This should prevent soiling of the mirror glass by spray water.